matplotlib._cntr deprecated

[neurodroid]

The matplotlib._cntr module (used for example here in CaImAn) has been removed from matplotlib and will be unavailable from version 2.2.0 onwards.
There's an alternative standalone contours module that provides similar functionality at the cost of adding a dependency.
Here's an example of how to replace matplotlib._cntr with the contours module.

[j-friedrich]

We already have skimage as dependency, hence replaced with skimage.measure.find_contours in dev and master.